EVALUATION OF INUNDATION RISK DURING HEAVY RAIN IN TOKYO 23 WARDS AND PRE-FLOODING OF UNDERPASS

Abstract

 Recently serious torrential rain event occurs frequently, whose intensity is much larger than the designed value for drainage network and urban rivers. To take proper countermeasure, reliable risk information based on more accurate numerical computation are required. In this study, the followings were confirmed by conducting numerical computation of urban area of western area from the Sumida river in 23 wards of Tokyo. The first is the effectiveness of existing rainwater countermeasures, and the second is the possibility to find the sign of inundation on underpass of road in drainage pipe as reverse flow to road.